DALLAS, TX - JUNE 09: LeBron James #6 of the Miami Heat stands on the court with his head down against the Dallas Mavericks in the fourth quarter of Game Five of the 2011 NBA Finals at American Airlines Center on June 9, 2011 in Dallas, Texas. (Photo by Mike Ehrmann/Getty Images)

(Photo by Mike Ehrmann/Getty Images)

MIAMI (CBSMiami.com) – The Miami Heat have been willing to face adversity head-on all season long.

But Sunday night, everything is on the line when the Heat welcome the Mavericks back to the AmericanAirlines Arena for Game 6 of the NBA Finals.

The Heat is down 3-2 in the best of seven series after dropping two-in-a-row in games that saw the Heat choke away big leads in the fourth quarter. But give credit to Dallas for taking the Heat out of their game and making them play the games the way Dallas wants to play them.

It’s literally now or never for the Heat; and after Game 5, the Heat players seemed to embrace the monumental challenge that is in front of them.

Despite a triple-double from LeBron James, the Heat couldn’t overcome one of the greatest shooting displays by a team in NBA Finals history. The Mavericks shot nearly 70 percent from three-point land and shot 56 percent overall in the game.

It was a statistical anomaly for any team, but it came at the worst possible time for the Heat. The Heat’s once-vaunted defense was shredded in the last two games in Dallas. And even though LeBron played better in Game 5, he didn’t want to hear about it.

Heat head coach Erik Spoelstra was happy with LeBron’s performance, even if fans weren’t.

“LeBron was much more aggressive tonight,” Spoelstra said. “Obviously, he had a triple-double. And he had an impact on the game.”

But Heat fans, and most media members covering the Finals, wanted to see LeBron become extremely aggressive on the offensive end of the court. Still, LeBron has been essentially relegated to playing point guard for parts of the game, which is a lot to ask of a guy who is 6’8”, 260 pounds.

LeBron displayed flashes of Magic Johnson in Game 5 making passes few other players could ever make. Now, for the Heat, it’s all about one thing: closing out a game.

When the Heat take the court at the AAA in Game 6, they will likely jump out to a lead. But, if the Heat wants to force a Game 7, they can’t take their foot off the gas for even a second.

“We’re going back home, so I think we’ve got all the momentum,” said Heat guard Mario Chalmers. “Two games left and we’re desperate.”

The Heat hasn’t played like a desperate team yet in the NBA Finals. Dwyane Wade, who has a hip bruise but will still play at full-strength in Game 6. , and especially LeBron, will have to leave everything they’ve got out on the court in Game 6 to get to a deciding Game 7.

“We’ll be better in Game 6,” LeBron said.

“We’re going home, and we wouldn’t have it any other way than the hard way,” Spoelstra said. “This is an opportunity for us. That’s why you play a seven-game series. You’ve got to play it out. And this is where we feel comfortable.”

And don’t think the Mavericks don’t know that they can’t relax now heading into Game 6.

“I really can’t enjoy much,” said Mavericks superstar Dirk Nowitzki. “In the playoffs, for some reason, you’re always on the edge. You don’t sleep much. You think basketball 24/7. I can enjoy it hopefully next week when we’re on vacation.”

“There’s really nothing to celebrate,” Nowitzki continued. “We’re going in there Sunday swinging, like we did today, from the jump, and hopefully steal one Sunday.”

Besides the Heat and all of their fans, there are two other groups desperate for a Game 7: ABC and the NBA. This is the most watched Finals in years and with the NBA heading for a lockout on July 1, the NBA needs all the good publicity it can get from a thrilling Finals going to Game 7.

In addition to the Mavericks and all of their fans, one other person desperately wants to see the Heat lose: Dan Gilbert, owner of the Cleveland Cavaliers. He will no doubt celebrate like no other if the Heat lose, but he should also realize, his team is a lot further from getting to an NBA title than the Heat is now.

And Heat fans should remember, once the season ends, win or lose, the Heat will be a much better team next year. Team president Pat Riley will have more money to play with and a mid-level exception to target a true point guard and center and more wing defenders off the bench with for the 2011-2012 season.